1. Field of the Invention
The invention relates to manufacturing methods of transparent electrode plates and organic flat emitting devices and, in particular, to manufacturing methods of transparent electrode plates and organic flat emitting devices having an insulation layer manufactured utilizing ink-jet printing technology.
2. Description of the Related Art
In recent years, light emitting devices are developed toward the trend of higher brightness, higher flatness, more compact, and lower power consumption. Therefore, OLED (organic light-emitting diode) or organic electroluminescent devices have become an important technology in the optical-electronic industry.
Referring to FIG. 1, the basic structure of a general organic light-emitting device 2 includes a transparent electrode plate 21, an organic electroluminescent layer 22, and a metallic cathode 23. The transparent electrode plate 21 includes a transparent substrate 211, a plurality of transparent anodes 212, and an insulation layer 213. FIG. 2A to FIG. 2C illustrate the conventional manufacturing method of the transparent electrode plate 21. First, referring to FIG. 2A, a transparent anode layer is coated on the transparent substrate 211. Then, an anode pattern shown in FIG. 2B is formed using lithography technology. Next, a polymer material with high resistance is spin-coated thereon. Afterwards, the pattern of the insulation layer 213 shown in FIG. 2C is formed using lithography technology. During the lithography process, photoresist and organic solution, such as developer and stripper, are required, and may cause environment pollution.
Conventionally, there are three major processes to manufacture the insulation layer. In the first process, photoresist-type polymer solution is employed to form the insulation layer, and is coated on the transparent substrate by spin coating and baking so as to form an insulation film. Then, the insulation layer structure is formed sequentially by exposing, baking, developing and baking. In the second process, non-photoresist-type polymer solution is used as the material of the insulation layer. The non-photoresist-type polymer solution is coated on the transparent substrate by spin coating and baking to form an insulation film. Then, the insulation layer structure is formed sequentially by photoresist coating, baking, exposing, developing, insulation layer etching, photoresist stripping and baking. In the third process, photosensitive/non-photosensitive polymer solution is used to form the insulation layer by screen-printing. To form the insulation layer by screen-printing, a screen having a specific pattern is placed on a substrate, and the insulation layer structure is formed by utilizing printing and curing (exposing/heating).
The first and second processes of manufacturing the transparent electrode plates mentioned above are both complex and time-consuming, and require various kinds of expensive manufacturing machines. The usage rate of the insulation layer material is very low (less than 10%), and the organic solution used during process causes environmental problems. The third process is simple and fast, but it still has the problems of low resolution of the insulation layer structure (larger than 150 m) and low material usage rate of the insulation layer (20% to 50%). The third process also occurs environmental problems, because large amount of organic solution is required to wash the screen.
To sum up, the manufacturing methods of organic flat emitting devices have the problems of various expensive manufacture machines, complex and time-consuming process, high costs, and environmental problems caused by using large amount of organic solution and photoresist. Furthermore, the fabrication of photomasks and screens further lengthens the manufacture cycle and raises the manufacture cost.